Digital Vernier Caliper 0-150mm

A bike comes in with a stubborn headset that the customer keeps tightening. The cup-and-cone adjustment is in spec, the fork crown clears the head tube cleanly, the bearings feel good. Five tries later, nothing's changed. The thing you haven't checked is whether the head tube itself has gone slightly oval. The 270A Digital Vernier Caliper is what tells you that in three seconds; by measuring the head tube ID at two perpendicular axes and reading the difference on the screen.

The 270A reads to a hundredth of a millimeter over a 0-150 mm range, in either millimeters or inches at the press of a button. The stainless steel frame holds calibration through everyday workshop handling; the digital readout removes the squint-and-interpret step that catches mechanics out on vernier scales the first few times they read one. Hard or soft jaws (the outside, inside, and depth jaws are all available on a single caliper) cover most measurement geometries you'll encounter on a working bench.

What it measures, in practical bike-shop terms

• Rotor thickness against the manufacturer's published minimum (Shimano typically 1.5 mm minimum on common road rotors)
• Axle outer diameter when sourcing a matching dust seal or bearing
• Head-tube ID across two perpendicular axes (the oval-detection check)
• Steerer outer diameter at a sleeved section vs. an unsleeved section
• Cassette spacer thickness when verifying a 142x12 vs. 148x12 conversion
• Spoke length (with the depth jaw extended) when verifying a wheel build's spoke order

The 270A is a precision instrument. That means it gets damaged by being dropped on a concrete floor, by being soaked in parts cleaner, or by being run through the bench grinder by mistake (yes, this has happened). It's worth its case.

Specs

• 0–150 mm / 0–6" range
• Digital readout (Unior corporate spec sheet for published resolution)
• Stainless steel frame
• Outside, inside, and depth jaws
• mm / inch toggle
• Storage case included
• 1-year warranty
• Article number: 270A

Built in Zreče, Slovenia

Unior has been forging hand tools in Zreče since 1919, and is the official technical partner of multiple World Tour and downhill teams. The 270A is the digital companion to our analog Vernier Caliper 271. Both live in different parts of the workflow; the digital reads fast and authoritative on the bench; the analog gets dropped without consequence in the road kit. Most working shops own both.

Pro tip from our mechanics

The single best diagnostic for a customer's stubborn headset adjustment is verifying the head tube hasn't ovalized. A 0.05 mm difference across the head tube ID is enough to drive a customer crazy with a headset that won't stay adjusted. Two seconds with the 270A and you have the answer. Our workshop hand tools guide covers the measurement layer of the shop in detail: Workshop hand tools every bike shop needs →